Back on November 30, when the OPEC cartel of oil producers collectively agreed to cut production, the Saudis agreed to cut to 10.058 million barrels a day. The latest increase therefore still keeps production below the agreed-upon number.

"The renewed weakness in oil prices is likely to put more pressure on OPEC members to agree to extend the output cuts beyond June," Tom Pugh, commodities economist at Capital Economics, wrote. "Indeed, we think it is now more likely than not that there will be some sort of extension to the deal to ensure that stocks are drawn down to more normal levels."